the results took 0.15 seconds on the regular Google search, and 0.09 seconds on Caffeine.-PC World
"For the last several months, a large team of Googlers has been working on a secret project: a next-generation architecture for Google's web search. It's the first step in a process that will let us push the envelope on size, indexing speed, accuracy, comprehensiveness and other dimensions. The new infrastructure sits "under the hood" of Google's search engine, which means that most users won't notice a difference in search results. But web developers and power searchers might notice a few differences, so we're opening up a web developer preview to collect feedback."
Google's head of spam team, cuts hair... well after that story he explains what google caffiene really is here